Arterial hypertension is one of the most important causes of cardiovascular morbidity and mortality. A possible solution for this problem can be the use of an ablation procedure for ablation of tissues via delivery of radio-frequency (RF) energy.
Some of the existing renal artery RF ablation systems involve energy transfer via an inflated balloon that can be built on an Over-The-Wire (OTW) shaft platform. Some of these balloon concepts can include a fluid circulation loop or flow loops to provide cooling during the ablation cycle. Flow loops can be created to serve several different purposes i.e., temperature regulation, drug delivery, continuous monitoring, etc. The flow paths for the system can be created using several designs. While there can be several advantages to an OTW system, one of the main drawbacks of such catheters can be the difficulty in fine-tuning the fluid inlet and outlet flow rates. Understanding and controlling the inlet flow and the outlet flow (i.e., back pressure) is critical to the catheter system as it directly impacts balloon sizing.
An alternative to OTW catheter systems is the rapid exchange platform. In rapid exchange catheters, a guide wire is positioned adjacent to the inlet and outlet lumens. A rapid exchange port connects the guide wire lumen to the external surface of the catheter body. The rapid exchange port provides a means for quickly removing one type of catheter and threading a new catheter onto the guide wire while maintaining the guide wire in place relative to the target area. An example of a rapid exchange catheter is described in U.S. Pat. No. 6,997,899, which is hereby incorporated by reference. Compared to OTW catheters, rapid exchange catheters allow the use of a shorter guide wire and facilitate control of inlet and outlet flow rates. A drawback of rapid exchange catheters is that, compared to the OTW catheters, the rapid exchange configuration requires a larger catheter profile in order to obtain a given flow rate.
Thus, there exists a need for a medical device with multi-shaft and multi-lumen design that can allow independent fine-tuning of the inlet and outlet lumen sizes while providing a separate lumen that can be accessed to form a rapid-exchange wire port. Likewise, there is a need to maximize inflow and outflow cross-sectional areas for fluidic transport while maintaining the lowest possible device profile. In RF ablation catheters, there is also a need to establish circulation in the catheter balloon while maintaining concentricity of the balloon with respect to the RF transmitter.
Without limiting the scope of the invention, a brief summary of some of the claimed embodiments of the invention is provided below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention can be found in the detailed description of the invention.
A brief abstract of the technical disclosure in the specification is provided as well for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.